TY  - CONF
AU  - Arcon, Iztok
AU  - Janvit, Terzan
AU  - Djinovic, Petar
AU  - Maxim, Zabilsky
AU  - Albin, Pintar
TI  - Operando XAS analysis of CuO/SiO<sub>2</sub> and CuO/CeO<sub>2</sub> catalysts
M1  - PUBDB-2018-03455
PY  - 2018
N1  - Book of abstracts available online at: https://exrs2018.ijs.si/abs/exrs2018-book.pdf
AB  - The possibilities of the operando XAS analysis of catalysts will be presented on two casestudies of promising new catalytic materials: alkali doped nano-dispersed copper oxideclusters on ordered mesoporous SiO2, which is highly active and selective towards propyleneepoxidation [1], and nanoshaped CuO/CeO2 catalysts used in N2O decomposition reaction [2].Operando Cu K-edge and Ce L3-edge XANES and EXAFS analysis was performed duringcatalytic reactions under controlled reaction conditions in a tubular reactor filled withprotective He atmosphere at 1 bar. The spectra were measured before the reaction at RT, thenduring heating, and during catalytic reaction at 400 °C under controlled atmosphere.Operando XANES analysis is used to monitor the changes in valence states and localsymmetries of Cu and Ce cations in the catalysts. A partial reduction of Cu2+ to Cu+ and Cu0and Ce4+ to Ce3+ species was detected during catalyst activation, and re-oxidation duringcatalytic reaction. Different dynamics of reaching a quasi-steady oxidation state were revealedas the tested catalysts approached the quasi-steady state after 300 min of reaction.Operando EXAFS spectra are used to precisely determine local structure of Cu and Cecations, to identify structural characteristics and changes of Cu and Ce species during thecatalytic reactions. In this way, the active site in the catalytic reactions can be identified andthe mechanism of the reaction clarified.The results of operando XAS analyses are crucial to guide further material modification, toobtain more effective catalyst, and material which is more resistant to inhibiting effects thatcause catalyst deactivation during catalytic reaction.
T2  - European Conference on X-Ray Spectrometry
CY  - 24 Jun 2018 - 29 Jun 2018, Ljubljana (Slovenia)
Y2  - 24 Jun 2018 - 29 Jun 2018
M2  - Ljubljana, Slovenia
LB  - PUB:(DE-HGF)6
DO  - DOI:10.3204/PUBDB-2018-03455
UR  - https://bib-pubdb1.desy.de/record/409610
ER  -